Why does melanoma metastasize into the brain? Genes with pleiotropic effects might be the key

Incidence and comparative prognosis of cancers with metastasis to noncommon sites: A population-based study

Primary tumors have common sites of metastasis such as lymph nodes, bones, liver, lungs, and brain; however, they can also metastasize to other uncommon sites such as adrenals, bone marrow, and skin among others. Our study aimed to investigate the relationship between uncommon sites of metastasis at the time of diagnosis and median survival in a number of primary tumors using the Surveillance, Epidemiology, and End Results (SEER) database. This retrospective cohort study conducted between September-October 2021 included patient-level SEER data for 2016-2018 using SEER Research Data, 9 Registries, Nov 2020 Sub (1975-2018). Descriptive analysis for complete cohort and median survival for each primary within the cohort was performed using R software. A total of 25,345 patients (females, 51.4%) were diagnosed with primary tumors with metastasis to uncommon sites at the time of diagnosis; the mean age at diagnosis was 68 years. Lung and bronchus primaries constituted the largest proportion of cohort (41.9%) that metastasized to uncommon sites, followed by nonHodgkin lymphoma-nodal (7.4%), pancreas (6.6%), stomach (3.7%), and ovarian (3.4%). The incidence of metastasis to uncommon sites was most common in respiratory cancers in ages 61-80 years (25%) and least in breast primaries in ages 18-40 years (0.1%), and was higher in Whites compared to other races. Regarding median survival, liver cancer with metastasis to uncommon sites had the worst prognosis (1 month), whereas small intestine tumors were associated with a better prognosis, median survival of 13 months. In this cohort study, the lung and bronchus cancers were the most common primaries metastasized to uncommon sites at diagnosis. The liver tumor had the worst survival compared to other tumors. These findings will help redirect the available screening tools to improve survival in patients with primary tumors with metastasis at diagnosis and may also play an essential role in future research and achieve a better prognosis for cancer patients.

MDM2/MDM4 amplification and CDKN2A deletion in metastatic melanoma and glioblastoma multiforme may have implications for targeted therapeutics and immunotherapy

Metastatic melanoma has a five-year survival of ~10%, with a paucity of biomarkers predicting metastasis to specific anatomic sites or targeted therapies for metastases. We analyzed 1015 primary and 358 metastatic melanomas and found metastatic disease is enriched for MDM2 and MDM4 amplifications compared to primary disease, and amplifications are associated with lower overall survival. MDM2/4 amplifications are associated with a higher rate of metastasis to the brain and liver. Two negative regulators of p53, USP7 and PPM1D, are also altered in metastatic melanoma compared to primary disease. These findings suggest that patients with metastatic melanoma have a dysregulated TP53 pathway compared to primary disease. We propose that patients with metastatic melanoma and wild-type TP53 may be more likely to benefit from MDM2, MDM4, USP7, and PPM1D inhibitors. Patients with MDM2/4 amplification display deep deletions in CDKN2A, alterations also associated with a higher rate of metastasis to the brain. Patients with a CDKN2A deletion have a higher rate of alterations in TTN, MUC16, LRP1B, and NF1, alterations previously associated with favorable response to immune-checkpoint inhibitors in melanoma. We propose CDKN2A alteration as a potential biomarker to predict response to immunotherapy in melanoma. We found that GBM displays the highest rate of MDM4 amplifications (9.63%) and CDKN2A deletions (54.39%) across all cancer types. In 592 GBM samples we found that 8.45% display MDM2 amplification. We suggest that patients with melanoma or GBM and amplifications in MDM2/4 and CDKN2A alterations may benefit from combinations of targeted inhibitors of MDM2/4 and CDK4/6, as well as immunotherapy.

Effect of calprotectin subunit S100A9 on the expression and methylation of OCLN in human melanoma cell line A-375

Increased levels of calprotectin subunits S100A8 and S100A9 have been detected in human cancers. Melanoma is the most aggressive type of skin cancer, and its treatment is challenging because of its brain metastasis. OCLN encodes occluding, which plays a major role in the formation and regulation of tight junctions. The aim of this study was to evaluate the methylation status of the OCLN promoter and its expression in A-375 melanoma cells treated with or without various concentrations of S100A9 for 24, 48, and 72 h. Total RNA was extracted, and synthesized cDNA was assessed by performing real-time PCR. MSP-PCR was performed after treatment with bisultfie. Recombinant S100A9 inhibited the proliferation of the A-375 cell line and the expression of the OCLN gene was downregulated in a time- and concentration-dependent manner. Results of MSP-PCR showed that the OCLN gene promoter in a human melanoma cell line (A-375) was semimethylated.